A switch of this type is already known (U.S. Pat. No. 3,665,135). It comprises a casing connected to ground and a conductor support mounted in the casing via an insulator. Two switch elements are mounted in the conductor support, perpendicularly to each other. These switch elements enable two conductor bars that are likewise perpendicular to each other to be interconnected. One of the conductor bars may also be grounded.
Also known (GB 1 329 725) is a high voltage electrical disconnector having three switch positions, including a grounding position. Two conductor bars situated in line with each other are connected to a casing that is closed in gastight manner. A switch element is mounted perpendicularly to the conductor bars. The element moves between a first position in which the two conductor bars are connected to each other, and a grounding position in which one of the conductor bars is grounded. In an intermediate, third position, the contact is open. In that device, the clearance is perpendicular to the travel axis of the switch element. Nevertheless, the stationary contact is not substantially annular in shape.
Also known (WO 2005/018066) is an electric switch comprising a switch element having a contact finger parallel to a travel direction of the switch element.
The document FR 1 543 152 discloses a switch with ring shaped fixed contacts and with a longitudinally movable commutation rod able to make contact between the fixed contacts. A contact is arranged in the axis of the commutation rod and a fixed contact encircles the communication rod. A semi movable contact arranged on an insulating tube encircles the rod and makes contact to the fixed ring shaped contact from the inside. However, for switching an additional commutation rod is needed. The insulating tube itself is not able to make a complete switching function.
The U.S. Pat. No. 5,955,715 discloses a circuit breaker with a first ring shaped fixed contact and a first ring shaped movable contact able to make contact and to separate depending on the position, the fixed contact being arranged on the axis of the movable contact; with a second ring shaped fixed contact and a movable commutation rod able to make contact and to separate, depending on the position, the fixed contact being arranged on the axis of the movable commutation rod; and with a third ring shaped fixed arcing contact and a semi moving block with a third ring shaped arcing contact able to make contact and to separate, depending the position. The semi moving block is sliding on the metal conductor rod. The third ring shaped contact encircles the metal conductor rod.